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diff --git a/servo/components/style/properties/computed_value_flags.rs b/servo/components/style/properties/computed_value_flags.rs
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+++ b/servo/components/style/properties/computed_value_flags.rs
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Misc information about a given computed style.
+
+bitflags! {
+    /// Misc information about a given computed style.
+    ///
+    /// All flags are currently inherited for text, pseudo elements, and
+    /// anonymous boxes, see StyleBuilder::for_inheritance and its callsites.
+    /// If we ever want to add some flags that shouldn't inherit for them,
+    /// we might want to add a function to handle this.
+    #[repr(C)]
+    pub struct ComputedValueFlags: u16 {
+        /// Whether the style or any of the ancestors has a text-decoration-line
+        /// property that should get propagated to descendants.
+        ///
+        /// text-decoration-line is a reset property, but gets propagated in the
+        /// frame/box tree.
+        const HAS_TEXT_DECORATION_LINES = 1 << 0;
+
+        /// Whether line break inside should be suppressed.
+        ///
+        /// If this flag is set, the line should not be broken inside,
+        /// which means inlines act as if nowrap is set, <br> element is
+        /// suppressed, and blocks are inlinized.
+        ///
+        /// This bit is propagated to all children of line participants.
+        /// It is currently used by ruby to make its content unbreakable.
+        const SHOULD_SUPPRESS_LINEBREAK = 1 << 1;
+
+        /// A flag used to mark text that that has text-combine-upright.
+        ///
+        /// This is used from Gecko's layout engine.
+        const IS_TEXT_COMBINED = 1 << 2;
+
+        /// A flag used to mark styles under a relevant link that is also
+        /// visited.
+        const IS_RELEVANT_LINK_VISITED = 1 << 3;
+
+        /// A flag used to mark styles which are a pseudo-element or under one.
+        const IS_IN_PSEUDO_ELEMENT_SUBTREE = 1 << 4;
+
+        /// Whether this style's `display` property depends on our parent style.
+        ///
+        /// This is important because it may affect our optimizations to avoid
+        /// computing the style of pseudo-elements, given whether the
+        /// pseudo-element is generated depends on the `display` value.
+        const DISPLAY_DEPENDS_ON_INHERITED_STYLE = 1 << 6;
+
+        /// Whether this style's `content` depends on our parent style.
+        ///
+        /// Important because of the same reason.
+        const CONTENT_DEPENDS_ON_INHERITED_STYLE = 1 << 7;
+
+        /// Whether the child explicitly inherits any reset property.
+        const INHERITS_RESET_STYLE = 1 << 8;
+
+        /// Whether any value on our style is font-metric-dependent on our
+        /// primary font.
+        const DEPENDS_ON_SELF_FONT_METRICS = 1 << 9;
+
+        /// Whether any value on our style is font-metric-dependent on the
+        /// primary font of our parent.
+        const DEPENDS_ON_INHERITED_FONT_METRICS = 1 << 10;
+
+        /// Whether the style or any of the ancestors has a multicol style.
+        ///
+        /// Only used in Servo.
+        const CAN_BE_FRAGMENTED = 1 << 11;
+
+        /// Whether this style is the style of the document element.
+        const IS_ROOT_ELEMENT_STYLE = 1 << 12;
+
+        /// Whether this element is inside an `opacity: 0` subtree.
+        const IS_IN_OPACITY_ZERO_SUBTREE = 1 << 13;
+
+        /// Whether there are author-specified rules for border-* properties
+        /// (except border-image-*), background-color, or background-image.
+        ///
+        /// TODO(emilio): Maybe do include border-image, see:
+        ///
+        /// https://github.com/w3c/csswg-drafts/issues/4777#issuecomment-604424845
+        const HAS_AUTHOR_SPECIFIED_BORDER_BACKGROUND = 1 << 14;
+
+        /// Whether there are author-specified rules for padding-* properties.
+        ///
+        /// FIXME(emilio): Try to merge this with BORDER_BACKGROUND, see
+        /// https://github.com/w3c/csswg-drafts/issues/4777
+        const HAS_AUTHOR_SPECIFIED_PADDING = 1 << 15;
+    }
+}
+
+impl ComputedValueFlags {
+    /// Flags that are unconditionally propagated to descendants.
+    #[inline]
+    fn inherited_flags() -> Self {
+        Self::IS_RELEVANT_LINK_VISITED |
+            Self::CAN_BE_FRAGMENTED |
+            Self::IS_IN_PSEUDO_ELEMENT_SUBTREE |
+            Self::HAS_TEXT_DECORATION_LINES |
+            Self::IS_IN_OPACITY_ZERO_SUBTREE
+    }
+
+    /// Flags that may be propagated to descendants.
+    #[inline]
+    fn maybe_inherited_flags() -> Self {
+        Self::inherited_flags() | ComputedValueFlags::SHOULD_SUPPRESS_LINEBREAK
+    }
+
+    /// Returns the flags that are always propagated to descendants.
+    ///
+    /// See StyleAdjuster::set_bits and StyleBuilder.
+    #[inline]
+    pub fn inherited(self) -> Self {
+        self & Self::inherited_flags()
+    }
+
+    /// Flags that are conditionally propagated to descendants, just to handle
+    /// properly style invalidation.
+    #[inline]
+    pub fn maybe_inherited(self) -> Self {
+        self & Self::maybe_inherited_flags()
+    }
+}